Today’s Wonder of the Day was inspired by Liam . Liam Wonders, “What is the purpose of the Nazca lines?” Thanks for WONDERing with us, Liam !

What human achievements amaze you in today's world? Do you stand in awe of buildings that stretch 100 stories or more into the sky? How about bridges that span miles of water? With all of the modern technology at our disposal, it can be easy to take such feats for granted.

Historians will tell you, however, that some of the most impressive feats of human achievement occurred hundreds, even thousands, of years ago. One needs to look no further than the Great Pyramids of Egypt, for example. Some of these feats boggle the mind when one considers that they were achieved without modern technology.

One such feat can be dated back 2,000 years or more. In fact, it was so impressive that it remained virtually unknown until after humans invented the airplane and took to the skies. Let's take a trip to the coastal plains of Peru to explore the Nazca Lines.

About 250 miles south of Lima, Peru, you'll find the arid desert plains of the Rio Grande de Nazca river basin. This area receives less than one inch of rain each year, making it one of the driest places on Earth.

It's also home to the Nazca Lines, a sprawling collection of huge geoglyphs: lines, shapes, and designs etched into the ground. The Nazca Lines are so large and cover such a large area (about 290 square miles) that they can really only be viewed from the air, which is why they remained virtually unknown until planes began flying over Peru in the 1930s.

Scientists believe the geoglyphs were created by the ancient Nazca culture approximately 2,000 years ago. The Nazca Lines consist of over 800 straight lines (some of which are about 30 miles long), more than 300 geometric designs (triangles, rectangles, trapezoids, spirals, arrows, wavy lines, etc.), and approximately 70 pictorial representations of plants and animals (called biomorphs), including a dog, lizard, duck, spider, hummingbird, monkey, whale, llama, cactus, flower, and tree.

Scientists believe the lines were made by carefully removing the top 12-15 inches of rust-colored pebbles that line the desert floor. Doing so reveals a layer of lighter-colored sand below. When you see the scale of the Nazca Lines from above, you gain an appreciation for what a monumental feat this was.

Fortunately, the lack of rain combined with the fact that the desert area gets little wind and suffers little erosion means the Nazca Lines have changed very little over the last two centuries. But why were they created in the first place?

Although the Nazca Lines have been studied for more than 80 years and were designated a UNESCO World Heritage Site in 1994, they remain largely a mystery. Theories abound, but scientists still don't know definitively why the Nazca Lines were created.

The first scientists to study the Nazca Lines believed they may have corresponded to important calendar events or astronomical phenomena. Others believe they were made by aliens. Later studies have led researchers to believe that the geoglyphs may point to places where important rituals were held to pray to ancient gods for rain.

The Nazca Lines will continue to be studied to learn more about how and why an ancient culture created these lasting marks on the desert floor. They'll also be the focus of renewed conservation efforts.

Although there's relatively little threat from Mother Nature, human beings are another issue. In 2014, members of environmental group Greenpeace damaged an area near the hummingbird geoglyph during a publicity stunt. Then, in 2018, a commercial truck driver drove over part of the Nazca Lines, damaging an area approximately 100 feet by 330 feet.

Wonder What's Next?

Join us in Wonderopolis tomorrow for a closer look at a very photogenic hound!